A comparison between use of spray and freeze drying techniques for preparation of solid self-microemulsifying formulation of valsartan and in vitro and in vivo evaluation

3D printed capsule shells for personalized dosing of cyclosporine-loaded SNEDDS

Cyclosporine (CsA) is a potent immunosuppressant agent that has been used since 1980 for the treatment of various autoimmune diseases and is extensively used to enhance the survival rate of patients and grafts following organ transplant surgeries. CsA is a poorly soluble drug with a narrow therapeutic window and inter-subject variability, which can lead to graft rejection, nephrotoxicity and other severe adverse effects. This study explores a novel method that combines solubility enhancement of CsA using SNEDDS formulation and personalized dosage delivery using 3D printing technology. The oil phase was chosen as a combination of caproyl 90 and octanoic acid while the Smix phase was chosen as a combination of cremophore El and PEG 400. The optimized liquid SNEDDS was solidified using PEG 6000. An FDM printer was used to print a capsular shell with an oval base that ascends to form a dome with an opening at the top. This opening is used to fill the molten CsA-loaded SNEDDS formulation using a pipette or syringe. The CsA-loaded SNEDDS formulation was characterized by FTIR, DSC and SEM/EDX. The in-vitro release of CsA showed complete release within sixty minutes and followed Korsmeyer-Peppas release kinetics. The drug release was not affected by either the shell opening size or the amount of the loaded formulation. This novel method is simple and straightforward for personalized dosage delivery of drug-loaded SNEDDS formulations.

Solidification of Self-Emulsifying Drug Delivery Systems as a Novel Approach to the Management of Uncomplicated Malaria

Malaria affects millions of people annually, especially in third-world countries. The mainstay of treatment is oral anti-malarial drugs and vaccination. An increase in resistant strains of malaria parasites to most of the current anti-malarial drugs adds to the global burden. Moreover, existing and new anti-malarial drugs are hampered by significantly poor aqueous solubility and low permeability, resulting in low oral bioavailability and patient noncompliance. Lipid formulations are commonly used to increase solubility and efficacy and decrease toxicity. The present review discusses the findings from studies focusing on specialised oral lipophilic drug delivery systems, including self-emulsifying drug delivery systems (SEDDSs). SEDDSs facilitate the spontaneous formation of liquid emulsions that effectively solubilise the incorporated drugs into the gastrointestinal tract and thereby improve the absorption of poorly-soluble anti-malaria drugs. However, traditional SEDDSs are normally in liquid dosage forms, which are delivered orally to the site of absorption, and are hampered by poor stability. This paper discusses novel solidification techniques that can easily and economically be up-scaled due to already existing industrial equipment that could be utilised. This method could, furthermore, improve product stability and patient compliance. The possible impact that solid oral SEDDSs can play in the fight against malaria is highlighted.

Relative bioavailability enhancement of simvastatin via dry emulsion systems: comparison of spray drying and fluid bed layering technology

Comprehensive comparisons of similar lipid based drug delivery systems produced by different technologies are scarce. Spray drying and fluid bed layering technologies were compared with respect to the process and product characteristics of otherwise similar simvastatin loaded dry emulsion systems. Fluid bed layering provided higher process yield (83.3% vs 71.5%), encapsulation efficiency (80.0% vs 68.4 %), relative one month product stability (93.8% vs 85.5%), larger and more circular particles (336 µm vs 56 µm) and lower median oil droplet size after product reconstitution in water (2.85 µm vs 4.27 µm), compared to spray drying. However, spray dried products exhibited higher drug content (22.2 mg/g vs 9.34 mg/g). An in-vivo pharmacokinetic study in rats was performed and a pharmacokinetic model was developed in order to compare the optimised simvastatin loaded dry emulsion systems, a simvastatin glyceride mimetic loaded in the dry emulsion and a simvastatin loaded SMEDDS with a reference physical mixture. Of the formulation tested, fluid bed layered pellets excelled and provided a 115% relative increase in bioavailability. Among the two technologies, fluid bed layering provided dry emulsion products with higher relative bioavailability and better product characteristics for further processing into final dosage forms.

Design and physico-mechanical evaluation of fast-dissolving valsartan polymeric drug delivery system by electrospinning method

Objective(s):

Chronic hypertension is a pervasive morbidity and the leading risk factor for cardiovascular diseases. Valsartan, as an antihypertensive drug, has low solubility and bioavailability. The application of orodispersible films of valsartan is suggested to improve its bioavailability. With this dosage form, the drug dissolves rapidly in saliva and is absorbed readily without the need for water.

Materials and Methods:

For this purpose, valsartan with polyvinylpyrrolidone (PVPK90) polymer were exposed to the electrospinning technique to construct orodispersible nanofilms. The optimum obtained nanofiber, selected by Design-Expert software, was evaluated in terms of mechanical strength for evaluation of the flexibility and fragility of the nanofibers. The drug content, wettability, and disintegration tests, as well as the release assessment of the nanofibers, were performed followed by DSC, FTIR, and XRD assays.

Results:

The uniform nanofibers’ diameter increased with the increase of the polymer concentration. The tensile test verified a stress reduction at the yield point as the polymer concentration increased. Then, the 492 nm nanofiber with above 90% drug encapsulation, containing 8% polymer and 18% valsartan made below 9 kV, was selected. The wetting time was less than 30 sec and over 90% of the drug was released in less than 2 min. The XRD and DSC studies also confirmed higher valsartan solubility due to the construction alternations in nanofibers. The FTIR examination indicated the chemical bonding between the drug and the polymer.

Conclusion:

The selected nanofibers of valsartan present the essential drug feature and acceptable drug release for further investigations.

3D Printing of Dapagliflozin Containing Self-Nanoemulsifying Tablets: Formulation Design and In Vitro Characterization

The 3D printing techniques have been explored extensively in recent years for pharmaceutical manufacturing and drug delivery applications. The current investigation aims to explore 3D printing for the design and development of a nanomedicine-based oral solid dosage form of a poorly water-soluble drug. A self-nanoemulsifying tablet formulation of dapagliflozin propanediol monohydrate was developed utilizing the semisolid pressure-assisted microsyringe (PAM) extrusion-based 3D printing technique. The developed formulation system consists of two major components (liquid and solid phase), which include oils (caproyl 90, octanoic acid) and co-surfactant (PEG 400) as liquid phase while surfactant (poloxamer 188) and solid matrix (PEG 6000) as solid-phase excipients that ultimately self-nanoemulsify as a drug encapsulated nanoemulsion system on contact with aqueous phase/gastrointestinal fluid. The droplet size distribution of the generated nanoemulsion from a self-nanoemulsifying 3D printed tablet was observed to be 104.7 ± 3.36 nm with polydispersity index 0.063 ± 0.024. The FT-IR analysis of the printed tablet revealed that no drug-excipients interactions were observed. The DSC and X-RD analysis of the printed tablet revealed that the loaded drug is molecularly dispersed in the crystal lattice of the tablet solid matrix and remains solubilized in the liquid phase of the printed tablet. SEM image of the drug-loaded self-nanoemulsifying tablets revealed that dapagliflozin propanediol monohydrate was completely encapsulated in the solid matrix of the printed tablet, which was further confirmed by SEM-EDS analysis. The in vitro dissolution profile of dapagliflozin-loaded self-nanoemulsifying tablet revealed an immediate-release drug profile for all three sizes (8 mm, 10 mm, and 12 mm) tablets, exhibiting >75.0% drug release within 20 min. Thus, this study has emphasized the capability of the PAM-based 3D printing technique to print a self-nanoemulsifying tablet dosage form with an immediate-release drug profile for poorly water-soluble drug.

Current Status of Supersaturable Self-Emulsifying Drug Delivery Systems

Self-emulsifying drug delivery systems (SEDDSs) are a vital strategy to enhance the bioavailability (BA) of formulations of poorly water-soluble compounds. However, these formulations have certain limitations, including in vivo drug precipitation, poor in vitro in vivo correlation due to a lack of predictive in vitro tests, issues in handling of liquid formulation, and physico-chemical instability of drug and/or vehicle components. To overcome these limitations, which restrict the potential usage of such systems, the supersaturable SEDDSs (su-SEDDSs) have gained attention based on the fact that the inclusion of precipitation inhibitors (PIs) within SEDDSs helps maintain drug supersaturation after dispersion and digestion in the gastrointestinal tract. This improves the BA of drugs and reduces the variability of exposure. In addition, the formulation of solid su-SEDDSs has helped to overcome disadvantages of liquid or capsule dosage form. This review article discusses, in detail, the current status of su-SEDDSs that overcome the limitations of conventional SEDDSs. It discusses the definition and range of su-SEDDSs, the principle mechanisms underlying precipitation inhibition and enhanced in vivo absorption, drug application cases, biorelevance in vitro digestion models, and the development of liquid su-SEDDSs to solid dosage forms. This review also describes the effects of various physiological factors and the potential interactions between PIs and lipid, lipase or lipid digested products on the in vivo performance of su-SEDDSs. In particular, several considerations relating to the properties of PIs are discussed from various perspectives.

MOF Capacitates Cyclodextrin to Mega-Load Mode for High-Efficient Delivery of Valsartan

PURPOSE

To investigate the mechanism of enhancing solubility and bioavailability of water-insoluble drug, valsartan (VAL), with being mega-loaded by cyclodextrin metal organic framework (CD-MOF).

METHODS

VAL was successfully mega-loaded into CD-MOF by magnetic agitation of VAL in ethanolic solution. Characterizations including powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), synchrotron radiation-based Fourier transform-infrared spectroscopy (SR-FTIR) ¹³C solid-state nuclear magnetic resonance spectroscopy ( ¹³C SS-NMR), nitrogen gas adsorption, and small-angle X-ray scattering (SAXS) were carried out to confirm the mechanism and incorporation behavior of VAL in CD-MOF. Ball milling process combined with molecular modeling was also used to confirm the mechanism. Improvement of bioavailability in vivo was confirmed by pharmacokinetic experiment in beagles.

RESULTS

As a carrier with payload 150% higher than conventional CD complexation, CD-MOF included molecules of VAL as complexations in the chambers of (γ-CD)₂, and nanoclusters in the confined spherical cages of (γ-CD)₆ confirmed by SAXS and ¹³C SS-NMR. Ball milling combined with molecular modeling inferred that the reduced release rate of the milled CD-MOF with ultrahigh drug payload was mainly due to the partial aggregation of the VAL nanoclusters. The molecules of VAL as nanoclusters in the cages of (γ-CD)₆ are critical in dramatically improving the apparent solubility (39.5-fold) and oral bioavailability (1.9-fold) of VAL in contrast to γ-CD inclusion.

CONCLUSIONS

The new understanding of drug nanoclusters in CD-MOF will help to design more efficient drug delivery systems using CD-MOF carrier with nanocavities.

Solidification to improve the biopharmaceutical performance of SEDDS: Opportunities and challenges

Self-emulsifying drug delivery systems (SEDDS) offer potential for overcoming the inherent slow dissolution and poor oral absorption of hydrophobic drugs by retaining them in a solubilised state during gastrointestinal transit. However, the promising biopharmaceutical benefits of liquid lipid formulations has not translated into widespread commercial success, due to their susceptibility to long term storage and in vivo precipitation issues. One strategy that has emerged to overcome such limitations, is to combine the solubilisation and dissolution enhancing properties of lipids with the stabilising effects of solid carrier materials. The development of intelligent hybrid drug formulations has presented new opportunities to harness the potential of emulsified lipids in optimising oral bioavailability for lipophilic therapeutics. Specific emphasis of this review is placed on the impact of solidification approaches and excipients on the biopharmaceutical performance of self-emulsifying lipids, with findings highlighting the key design considerations that should be implemented when developing hybrid lipid-based formulations.

Colloidal aspects of dispersion and digestion of self-dispersing lipid-based formulations for poorly water-soluble drugs

Self-dispersing lipid-based formulations, particularly self-microemulsifying drug delivery systems (SMEDDS) have gained an increased interest in recent times as a means to enhance the oral bioavailability of poorly water-soluble lipophilic drugs. Upon dilution, SMEDDS self-emulsify in an aqueous fluid and usually form a kinetically stable oil-in-water emulsion or in some rare cases a true thermodynamically stable microemulsion. The digestion of the formulation leads to the production of amphiphilic digestion products that interact with endogenous amphiphilic components and form self-assembled colloidal phases in the aqueous environment of the intestine. The formed colloidal phases play a pivotal role in maintaining the lipophilic drug in the solubilised state during gastrointestinal transit prior to absorption. Thus, this review describes the structural characterisation techniques employed for SMEDDS and the recent literature studies that elucidated the colloidal aspects during dispersion and digestion of SMEDDS and solid SMEDDS. Possible future studies are proposed to gain better understanding on the colloidal aspects of SMEDDS and solid SMEDDS.

Solubilisation behaviour of poorly water-soluble drugs during digestion of solid SMEDDS

Lipid based-formulations can enhance the bioavailability of poorly water-soluble lipophilic drugs through enhanced solubilisation of drugs in the gastrointestinal (GI) tract during digestion. This study investigates the solubilisation behaviour of poorly water-soluble drugs upon digestion of solid self-microemulsifying drug delivery system (S-SMEDDS). The S-SMEDDS were prepared using two different core lipids, Gelucire® 44/14 (GEL) or glyceryl monooleate (GMO), and were loaded with two model drugs, fenofibrate (FEN) and cinnarizine (CINN). S-SMEDDS formulations were characterized using wide-angle X-ray scattering (WAXS) and Raman spectroscopy, and their structural behaviour and drug solubilisation behaviour were monitored using drug-related diffraction peaks during digestion under fasted and fed simulated intestinal conditions using time-resolved small and wide-angle X-ray scattering (SAXS/WAXS). The concentrations of FEN and CINN released into the aqueous phase (AP) during digestion were quantified using high-performance liquid chromatography (HPLC). Both model drugs, FEN and CINN, had greater solubility in the GMO-based S-SMEDDS formulations and were partially solubilised into lipid matrix and uniformly distributed in solid formulations. The extent of digestion was greater for the GEL-based systems (92-94%) than GMO-based systems (65-75%) as was the rate of digestion. GEL-based S-SMEDDS formulations formed a lamellar phase during digestion in the fasted state and formed mixed micelles in the fed state. In contrast, the GMO-based system formed the mixed micelles in both intestinal conditions. The time-resolved SAXS profiles revealed solubilisation of crystalline drugs into the lipolysis products. Synchrotron SAXS results were in correlation with the HPLC measurements, confirming the ability of the SAXS technique to monitor drug behaviour and showing that the digestion of S-SMEDDS can enhance drug solubilisation.

Influence of Sodium Alginate on Hypoglycemic Activity of Metformin Hydrochloride in the Microspheres Obtained by the Spray Drying

Alginate microspheres with metformin hydrochloride were prepared by the spray drying method in order to improve residence time of drug in the stomach. Nine formulations (F1–F9) with various drug : polymer ratio (1 : 2, 1 : 1, and 2 : 1) and different sodium alginate concentration (1%, 2%, and 3%) were evaluated for size, morphology, drug loading, Zeta potential, and swelling degree.In vitrodrug release, mathematical release profile, and physical state of microspheres were also evaluated. Optimal formulation characterized by the highest drug loading was formulation F6 (drug : polymer ratio 2 : 1 and 2% alginate solution). Based on glucose uptake inSaccharomyces cerevisiaecells andα-amylase inhibition tests, it could be concluded that alginate microspheres enhance hypoglycemic activity of metformin hydrochloride evaluatedin vitro. Designed microspheres are promising as alternative, multicompartment dosage form for metformin hydrochloride delivery.

Soluplus®/TPGS-based solid dispersions prepared by hot-melt extrusion equipped with twin-screw systems for enhancing oral bioavailability of valsartan

BACKGROUND

Soluplus(®) (SP) and D-alpha-tocopherol polyethylene glycol 1000 succinate (TPGS)-based solid dispersion (SD) formulations were developed by hot-melt extrusion (HME) to improve oral bioavailability of valsartan (VST).

METHODS

HME process with twin-screw configuration for generating a high shear stress was used to prepare VST SD formulations. The thermodynamic state of the drug and its dispersion in the polymers were evaluated by solid-state studies, including Fourier-transform infrared, X-ray diffraction, and differential scanning calorimetry. Drug release from the SD formulations was assessed at pH values of 1.2, 4.0, and 6.8. Pharmacokinetic study was performed in rats to estimate the oral absorption of VST.

RESULTS

HME with a high shear rate produced by the twin-screw system was successfully applied to prepare VST-loaded SD formulations. Drug amorphization and its molecular dispersion in the polymer matrix were verified by several solid-state studies. Drug release from SD formulations was improved, compared to the pure drug, particularly at pH 6.8. Oral absorption of drug in rats was also enhanced in SP and TPGS-based SD groups compared to that in the pure drug group.

CONCLUSION

SP and TPGS-based SDs, prepared by the HME process, could be used to improve aqueous solubility, dissolution, and oral absorption of poorly water-soluble drugs.

Extracellular ligninolytic enzymes production by Pleurotus eryngii on agroindustrial wastes

Pleurotus eryngii (DC.) Gillet (MCC58) was investigated for its ligninolytic ability to produce laccase (Lac), manganese peroxidase (MnP), aryl alcohol oxidase (AAO), and lignin peroxidase (LiP) enzymes through solid-state fermentation using apricot and pomegranate agroindustrial wastes. The reducing sugar, protein, lignin, and cellulose levels in these were studied. Also, the production of these ligninolytic enzymes was researched over the growth of the microorganism throughout 20 days, and the reducing sugar, protein, and nitrogen levels were recorded during the stationary cultivation at 28 ± 0.5°C. The highest Lac activity was obtained as 1618.5 ± 25 U/L on day 12 of cultivation using apricot. The highest MnP activity was attained as 570.82 ± 15 U/L on day 17 in pomegranate culture and about the same as apricot culture. There were low LiP activities in both cultures. The maximum LiP value detected was 16.13 ± 0.8 U/L in apricot cultures. In addition, AAO activities in both cultures showed similar trends up to day 17 of cultivation, with the highest AAO activity determined as 105.99 ± 6.3 U/L on day 10 in apricot cultures. Decolorization of the azo dye methyl orange was also achieved with produced ligninolytic enzymes by P. eryngii using apricot and pomegranate wastes.

Solid-nanoemulsion preconcentrate for oral delivery of paclitaxel: formulation design, biodistribution, and γ scintigraphy imaging

Aim of present study was to develop a solid nanoemulsion preconcentrate of paclitaxel (PAC) using oil [propylene glycol monocaprylate/glycerol monooleate, 4 : 1 w/w], surfactant [polyoxyethylene 20 sorbitan monooleate/polyoxyl 15 hydroxystearate, 1 : 1 w/w], and cosurfactant [diethylene glycol monoethyl ether/polyethylene glycol 300, 1 : 1 w/w] to form stable nanocarrier. The prepared formulation was characterized for droplet size, polydispersity index, and zeta potential. Transmission electron microscopy (TEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to assess surface morphology and drug encapsulation and its integrity. Cumulative drug release of prepared formulation through dialysis bag and permeability coefficient through everted gut sac were found to be remarkably higher than the pure drug suspension and commercial intravenous product (Intaxel), respectively. Solid nanoemulsion preconcentrate of PAC exhibited strong inhibitory effect on proliferation of MCF-7 cells in MTT assay. In vivo systemic exposure of prepared formulation through oral administration was comparable to that of Intaxel in γ scintigraphy imaging. Our findings suggest that the prepared solid nanoemulsion preconcentrate can be used as an effective oral solid dosage form to improve dissolution and bioavailability of PAC.